Receivers performing diversity functions are well known in the art for overcoming transmission errors. A particular type of diversity operation for receivers is known as antenna diversity. Receivers performing antenna diversity have an RF antenna switch before the demodulator to selectively receive RF signals from one or more antennas. Typically, the RF antenna switch is located at the input of the receiver.
A generic RF antenna switch is shown in U.S. Pat. No. 5,001,776. Several types of RF antenna switches for switching between RF signal paths are well known in the art. A reed switch used as an antenna switch is taught in U.S. Pat. No. 3,800,222. A circulator used as an antenna switch is taught in U.S. Pat. No. 4,380,822. A relay used as an antenna switch is taught in U.S. Pat. No. 4,982,442 and U.S. Pat. No. 5,060,293. A gallium arsenide field effect transistor is used as an antenna switch is taught in U.S. Pat. No. 4,920,285 and U.S. Pat. No. 4,987,382. A pin diode is also conventionally used as an RF antenna switch.
However, these conventional RF antenna switches have either high loss that reduces the receiver's sensitivity or high current drain. Portable receivers, such as radiotelephones, need high receiver sensitivity and low current drain. Therefore, there is a need for an RF antenna switch that has low loss and low current drain.